I was carrying the 190 PRO to Japan, going there is not a problem i bring along with me but when coming back during the security check they said is too long. As a result i have to go out and check the tripod into the cargo but i took out my head just in case. But i think it depend on luck or sometime which airport. I came back from Kansai Airport just for your information.
talk to custom/security/check-in nicely and advise them(expensive/delicate equipment/fragile etc) they bear the risk of damage the equipment, they allow me to hand carry in without problem. ;p
so far no problem even at the USA custom/check-in security.
YMMV